A refresh and support for Visual Studio 2019 for Righthand Dataset Debugger Visualizer

I had some spare time and decided to add support for Visual Studio 2019 to Righthand Dataset Debugger Visualizer. Along the path I decided to upgrade underlying DevExpress libraries to a more recent version and switch from Smart Assembly to ILMerge for assembly merging (the only reason is that ILMerge is open source and I wanted to test it). As a collateral I dropped support for Visual Studio 2015 and older versions. One can still use older versions of visualizers for that. The other collateral is that from now on there will be only a merged assembly version available (unless there are problems with merged ones).

So, there you have it, enjoy version 1.0.15